1. Field of the Invention
This invention relates to the field of systems and methods for recharging electric vehicles and to network-controlled electrical outlets used in such systems.
2. Description of the Related Art
The electric car, electric vehicle (EV) and battery electric vehicle are all used to describe automobiles powered by one or more electric motors utilizing energy stored in rechargeable batteries. The batteries are recharged by connecting to an electrical outlet. Efficient recharging of the batteries typically requires hours and is often done overnight or while the electric vehicle is parked for a significant time. The use of electric vehicles is limited by the sparse availability of recharging facilities. There is a need for more widespread recharging facilities. Furthermore, there is a need for more recharging facilities available where vehicles are parked for longer periods of time.
An important part of any consumer experience is the ease of acquiring a product—to recharge an electric vehicle this entails finding an available recharging facility, controlling the facility, and paying for the electricity consumed. There is a need for a communication network which facilitates finding the recharging facility, controlling the facility, and paying for the electricity consumed.
Electricity grids have periods of high demand from customers where the demand may approach or even exceed the electricity supply. Conversely, there are periods of low demand which coincide with high electricity production. Demand Response is a mechanism for reducing consumption of electricity during periods of high demand. For example, consumer services such as air conditioning and lighting may be reduced during periods of high demand according to a preplanned load prioritization scheme. Demand Response may also be used to increase demand at times of high electricity production. For example, the cost of electricity may be reduced during periods of low demand. Furthermore, some Demand Response systems encourage energy storage during periods of low demand, for release back into the electricity grid during periods of high demand. For example, battery electric vehicles may be charged during periods of low power demand and then release power back to the grid during periods of high demand.
Electric vehicles can be recharged from a local electricity grid. These vehicles can also be a source of electric power to be transferred to the local electricity grid. The transfer of electricity stored in electric vehicles to the local electric grid is referred to as vehicle-to-grid (V2G). V2G is particularly attractive for electric vehicles which have their own charging devices, such as battery electric vehicles with regenerative braking and plug-in hybrid vehicles. V2G is desirable for peak load leveling—helping to meet the demand for electricity when demand is at its highest. V2G is not widely available—it is principally being used in small pilot schemes. There is a need for more widely available Demand Response and V2G to assist with peak load leveling.
For Demand Response and V2G to be implemented effectively, real time communication of a need for power input into the local electricity grid is required. This communication from electric utility companies needs to reach recharging facility managers and electric vehicle owners and users. There is a need for an efficient communication network for managing peak load leveling using Demand Response and V2G.
Currently, a major source of revenue for building and maintaining highways for vehicular traffic is the gasoline tax. Should electric vehicles start to replace significant numbers of gasoline burning vehicles there will be a drop in tax revenues. To compensate for this loss in revenue, a tax on electricity consumption by electric vehicles may be imposed. Such a tax would require accurate measurement and reporting of electricity consumed by electric vehicles. Consequently, there will be a need for a system for collection of taxes and consumption information.
As is clear from the above discussion, communication networks are an essential part of electric vehicle recharging systems that will meet the needs of electric vehicle operators, recharging facility operators, utility companies and tax authorities. A survey of communication networks, ranging from local area networks to wide area networks, is provided below. There is a focus on wireless networks which would be accessible to mobile communication devices. A variety of mobile communication devices are also described.
A radio frequency identification transmitter, commonly referred to as an RFID transmitter, is used for short range communication with an RFID receiver. Typical ranges are of the order of one meter to tens of meters. An example of an RFID transmitter is a remote keyless entry device.
A radio frequency identification transceiver, commonly referred to as an RFID transceiver, is used for short range communication with an RFID transponder. (A transceiver is a device that has both a transmitter and a receiver.) Typical ranges are of the order of one meter for communication with passive transponders and hundreds of meters for communication with active transponders. The longer range of the active transponders is due to a power supply integrated into the transponder. RFID transponders store information which is broadcast over radio frequencies when prompted by a specific radio frequency signal from an RFID transceiver. An example of an RFID transponder is a FasTrak® card, primarily used for payment of automotive tolls in California. Each FasTrak® card has a unique code which is associated with a debit account. Each time a FasTrak® card passes through a toll collection point, the unique code is transmitted by the card in response to being interrogated by an RFID transceiver. The code is detected by the RFID transceiver and the toll is debited from the user's account.
A wireless personal area network (WPAN) radio frequency transceiver is used for radio frequency short range (typically within 1-100 meters) communication between devices. An example of such a device is a Bluetooth® transceiver, where Bluetooth® refers to a particular standard and protocol primarily designed for short range radio frequency communications. Another example is a ZigBee® transceiver, where ZigBee® refers to a standard and protocol designed for short range radio frequency communications. ZigBee® transceivers form mesh networks.
A wireless local area network transceiver is used for radio frequency communication over tens of meters or more between devices. An example of such a device is a Wi-Fi® device, where a Wi-Fi® device is one that is based on the IEEE 802.11 standard. Another example is a ZigBee® device—see discussion above. Wireless local area networks (WLANs) are typically configured to provide higher throughput and cover greater distances than wireless personal area networks (WPANs); a WLAN typically requires more expensive hardware to set up than a WPAN.
Power line communication (PLC) technology can be used to network computers over electrical power lines. This technology is restricted to short distances for high-speed transmission of large amounts of data. An alternating current line transceiver is used to enable PLC. A PLC network is another example of a LAN.
Wired local area networks (wired LANs), which include both wire and optical fiber, are also used to connect computers. A wired LAN is distinguished from a PLC LAN by the use of dedicated wires, used only for carrying communication signals and not used as a power lines. The Ethernet is the most widespread wired LAN technology.
Wide area networks (WANs) are computer networks that cover a broad geographical area—a network that crosses city, regional or national boundaries. The best known example of a WAN is the Internet. The Internet is a worldwide, publicly accessible plurality of interconnected computer networks that use a standard protocol—Transmission Control Protocol (TCP)/Internet Protocol (IP). Many local area networks are part of the Internet. There are also privately owned WANs. The World Wide Web (WWW), often referred to as the Web, is a collection of interconnected web pages. The Web is accessible via the Internet.
There is a need to effectively integrate these wide area networks, local area networks and short range communication devices into systems used for recharging electric vehicles.